Preheat oven to
350 degrees F. Place Gorgonzola in a small bowl. Add
the olive oil, pepper and mustard and mix until very well combined, about
1 minute.
Halve the bread lengthwise, leaving 1 long side attached. Spread cheese
mixture evenly over cut surface of both halves, leaving a 1/2-inch border
around outside edges. Place the bread halves together. Wrap loaves tightly
in foil. (Can be prepared 2 days ahead and refrigerated or 4 months ahead
and frozen. Let thaw before baking.) Bake until cheese melts, about 30
minutes.